15RACHI0P0DA. MOLLUSCA. TEREBRATULA. 141 



Genus TEREBRATULA, Brug. 



Shell inequivalve, one valve prolonged into a sort of heak^ and 

 -perforated at its tip for the passage of a tendinous cord by lohich it 

 affixes itself. On the interior of the smaller valve are two bony 

 processes. 



TerebrAtula caput-serpentis. 



Shell obovate, ivhitish^ upper valve truncated horizontally at the 

 apex ; foramen large, one side completed by the apex of the lower 

 valve ; surface with minute, radiating strice. 



State Coll., No. 145. Soc. Cab., No. 2348. 



Anomia caput-serpentis, Lin. ; Syst. jYat., 153. Born ; Miis., pi. 6, f. 14. 



Gmelin ; Si/si., 3344, No. 21. Chemn ; Corec/t., t. 78, f. 712. W ood ; Index, 



pi. Il,f. 22. 

 Terebratula, Brug. ; Encyc. Mith., pi. 24G, f. 7, a, b, c, d, e, f. 

 Terebratula caput-serpentis, 1.AM. .An. sans FerZ., vii. 332. 

 Anoinia pubescens, Dillwyn ; Catal., i. 293. 

 Terebratula pubescens, Deshayes ; Encyc. Milh., Vers, iii. 1024. Blainv. ; 



MalacoL, pi. 52, f. 6. Sowerbv ; Genera, f. 2. 

 Terebratula septentrionalis, Codthouv ; Bost. Journ. Jfat. Hist., ii. 65, pi. 3, f. 18. 



Shell rather thin, semi-transparent, yellowish or reddish-white, 

 broadly obovate ; upper valve slightly convex, narrow at the sum- 

 mit, and abruptly widening below ; beak slightly projecting, trun- 

 cated horizontally so as to form a large, semi-elliptical orifice, 

 completed below by the apex of the lower valve, which valve is 

 rounded, flattish, slightly protuberant down the middle ; both 

 valves covered by minute, but distinct and well-rounded radiating 

 ribs, which increase in number with the width of the shell ; these 

 are crossed by a few irregular lines of growth ; the whole covered 

 by a thin, silvery, fibrous epidermis. From under each tooth in 

 the lower valve arises a thin process curving a little inwards, 

 whose extremities support an oval, partially twisted ring of a 

 similar ribband-like structure, about an eighth of an inch in di- 

 ameter. Margin of the shell minutely toothed by the terminations 

 of the ribs. Length |i- inch, height i| inch, breadth /^ '"c'l. 



Found in considerable numbers in the stomachs of fish, and 

 occasionally on the sea-beach. It has also been taken alive on 



